The use of recycled oils and renewable raw materials in the production of transportation fuels and base oils for lubricants is an object of interest. The use of renewable raw materials of biological origin instead of non-renewable fossil raw materials for production of hydrocarbon components can be desirable. The fossil raw materials are exhaustible and they have harmful effects on atmosphere and environment.
Biological oils have previously been transesterified to form biodiesel (fatty acid methyl esters; FAME) and biolubricant components (lube esters). The use of lube esters is limited to a few special applications such as oils for refrigerator compressor lubricants, bio-hydraulic oils and metal working oils. Lube esters are used mainly in additive scale in regular automotive and industrial lubricants, because of the technical problems associated with them. Lube esters are polar compounds and suffer from greater seal-swelling tendency than pure hydrocarbons. In addition, lube ester oils are hydrolysed more easily to acids, which in turn cause corrosion on lubricating systems. Lubrication oils consisting of pure hydrocarbon structures are therefore favoured, since they do not suffer from these problems. It is therefore desirable to find ways of producing hydrocarbon containing lube oil components also from renewable sources.
Lube range components (C24-C43) can be produced from free fatty acids in a method where two free fatty acid molecules react with each other forming a ketone. The carbon number of the formed ketone back-bone is the sum of the carbon atoms in the two fatty acids minus one carbon, due to the release of one molecule of CO2 during the ketonisation reaction. The catalysts used in these reactions are typically metal oxides.
Metal oxide ketonisation catalysts suffer from several drawbacks. The catalysts cannot withstand the presence of double bonds or triglycerides during the ketonisation reaction, which both are typically present in biological oils. Therefore, compounds with double bonds must be saturated and triglycerides are generally removed prior to leading the feedstock into the ketonisation unit. This is typically performed by distilling the free fatty acids and employing a pre-hydrogenation unit before the actual ketonisation unit. Furthermore, if noble metal catalysts are used in the double bond hydrogenation, sulphur and nitrogen traces will shorten the catalyst life significantly by deactivation and passivation of the metal sites of the catalyst. The ketonisation units therefore can require a very cumbersome pre-treatment of the triglyceridic biological oils.
In addition, ketonisation reaction of fatty acids is typically done using gas phase introduction of free fatty acids. Due to the low vapour pressure of fatty acids, vaporisation of fatty acids needs much carrier gas, which requires a large unit.
Ketones can be hydrodeoxygenated to paraffins using a hydrotreatment catalyst at 200-350° C. and hydrogen pressure of 1-5 MPa. The n-paraffins formed by hydrodeoxygenation of ketones can be hydroisomerised and produce branched iso-paraffins (typically methyl-paraffins).

Formation of hydrocarbon base oil components by ketonisation of free fatty acids, using a metal oxide catalyst in gas phase is demonstrated in the publication WO2007068795, the metal in the metal oxide catalyst being preferably Na, Mg, K, Ca, Sc, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Y, Zr, Mo, Rh, Cd, Sn, La, Pb, Bi, or a rare earth metal on a laterite, bauxite, titanium dioxide, silica and/or aluminium oxide support. The formed ketones were subsequently hydrodeoxygenated and isomerized to paraffinic lube oil components. Publication EP 591297 describes a method for producing a ketone from fatty acids by pyrolysis reaction using a magnesium oxide catalyst. EP 0457665 discloses a method for producing ketones from triglycerides, fatty acids, fatty acid esters, fatty acid salts, and fatty acid anhydrides using a bauxite catalyst containing iron oxide. All these methods suffer from the above described disadvantages.
Production of a hydrocarbon mixture comprising fuel components and base oil components would be economically advantageously carried out utilising the same process unit or equipment. Base oil components are possible to retrieve as side products to some extent. However, the practical production process is challenging due to different requirements for reactions and reaction conditions.
Publication US2011107656 describes a method for processing triglyceride-containing, biologically-derived oils to provide for base oils and diesel fuels, wherein a partial oligomerization of unsaturated fatty acids contained therein yields a mixture from which the base oils and diesel fuels are extracted. Dimerization, trimerization or oligomerization of unsaturated fatty acids and following hydrodeoxygenation, forms highly branched and cyclic hydrocarbon components and even aromatic compounds. Viscosity index of these mixtures is rather high, typically greater than 120.
To overcome the above described deficiencies, there is an obvious need for a method to produce efficiently and simultaneously nonpolar, saturated and linear base oil components and fuel components complying with the quality requirements for high-quality base oils, from renewable sources.